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USB mic picks up a lot of noise when laptop is connected to power
| Pls send help, it kinda bugs me a lot.
| I have the reverse issue: when the laptop is charging, I hear a constant hum in my mic. Using cheap generic USB mic here, so I have two source of problem.
| >>314072
Actually it's ferrite, not graphite:
https://en.wikipedia.org/wiki/Ferrite_%28magnet%29?wprov=sfla1
See "uses"
| >>314072
Do I put it on the cable between the laptop and the AC/DC adapter, or between the adapter and the power outlet?
| >>314202
Arround the cable between the laptop and the adapter. I doubt the good old soviet wiring is the problem, but the evil capitalists AC/DC adaptor from the chinese traitors. I'm sure it's made of cheap capitalist components, which cause some noise frequencies.
| >>314376
Uhhh, the best I can get around here is a clamp-on ferrite bead, will that suffice? Also what do you mean by wrapping it several times through the ring? If it just barely fits the cable, could I just get several ferrite beads?
Also, I mean, old soviet wiring kinda could be the problem. The power outlets aren't grounded after all. That ought to be the root of this issue. But I can't do jack about that, so yeah. Thanks for the suggestion, though! I will try ferrite.
| Hm, apparently the power cable already has a small ferrite bead built in between the laptop itself and the adapter. Idunno if getting another one would help.
| >>314514
Maybe try it with a capacitor (again between laptop and ac/dc adapter, in parallel), to get rid of the noise, wherever it comes from. They only cost a few rubel. You also need a soldering iron, tin, a sharp knife and isolators, thought.
I know your problem, and I'm 90% sure it's the adapter causing noises. Usually there should be a galvanic separation and smoothing capacitors on the dc side.
| Funny thing: when I press on the power supply jack (the bit that goes into the laptop) with my fingers when near the mic it also gives slight noise, even though the laptop (and subsequently the mic itself) is not connected to it. It's the weirdest thing. Some kinda EM field maybe?
| >>315426
Stuff like crosstalk happens when cables are really close together. If so you could be conducting the electricity, lol!
| >>316315
Just put the tin foil arround.
Btw. sometimes also cooling fans make electrical (beside mechanical) noises.
Did you install a buffer/smoothing capacitor? It should definitely do the job.
| >>316620
Cooling fans definitely aren't the issue. It only happens when the laptop is charging. Guess I'll fiddle with foil as well as ferrites.
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| I know that it's an issue of the laptop not being grounded, the thing is that none of the power outlets in my flat are, it's an old soviet building with shitty wiring. Are there any ways to solve the issue with some kinda line filter or whatever, or am I just SOL? It's not that much of an issue, I suppose, but the constant hum is not that great obviously.